Lamp base



FIG. 1 is a top, three quarter view of the lamp base showing my new design, the fluorescent lamp being shown in broken lines for illustrative purposes only;

FIG. 2 is a front elevational view thereof on an enlarged scale, the rear being identical;

FIG. 3 is a right side elevational view thereof on an enlarged scale, the left side being identical;

FIG. 4 is a top plan view thereof on an enlarged scale;

FIG. 5 is a bottom plan view thereof on an enlarged scale. 

The ornamental design for a lamp base, substantially as shown and described. 